Pressure Induced Metastable Amorphization of BAs: Evidence for a Kinetically Frustrated Phase Transformation

A transformation from the zinc blende (zb) to an amorphous crystal structure was observed at 125 GPa, just slightly above the calculated equilibrium transition pressure to the rock salt phase Phys. Rev. B 36 6058 1987. This is the first evidence that pressure induced amorphization in AB compounds is a kinetically frustrated process. The amorphous state persisted on further loading to 165 GPa, and throughout down-loading to 0 GPa. The Birch coefficients of the equation of state for the zb phase were determined to be B₀=148±6 GPa and B₀^'=3.9±0.3, in good agreement with theoretical calculations.